Coating method



March 17, 194 N. P. HARSHBERGER COATING METHOD Original Filed April 29,1939 'INYENTOR, MmmZA mskzqzr 044 AT T o R N E Y Hm. I )IIIIIIIIIIIIIIIII III lllllll Patented Mar. 17, 1942 COATING'METHOD Norman P.Harshberger, Old Greenwich, Conn., assignor to Carbide and CarbonChemicals Corporation, New York, N. Y., a corporation of New YorkOriginal application .April 29, 1939, Serial No. 270,730. Divided andthis application May 27, 1941, Serial No. 395,372

14 Claims.

This invention relates to methods for coating particulate materials, forinstance, roofing granules, and to methods for producing continuouscoatings comprising particulate materials and a binder. The methods areparticularly applicable to making cement coated roofing and siding, forinstance, of the type disclosed in my prior Patent No. 1,913,667,granted June 13, 1933, wherein, for example, a felted fibrousbase issaturated and coated with a bitumen such as asphalt, then surfaced witha layer of granular particles, and subsequently surfaced on the granulesid with a cement composition.

The present invention is a continuation-inpart of my co-pendingapplication Serial No. 26,770, filed June 15, 1935, now Patent No.2,156,286 and is a division of my co-pending application Serial No.270,730, filed April 29, 1939.

Prior particulate coating methods have generally required large batchmixing and tumbling operations. Batch mixing has also been the casewhere it has been desired to provide coatings with aggregate material tofurnish coloring and filler properties. These methods require muchapparatus, many operations, and much handling of the materials.

The present invention aims to provide simple, efiicient and readilycontrolled methods for the purposes described.

An object of the invention is to provide a method for coating individualpieces of particulate material with coating compositions; in particular,compositions of a sludgy or plastic consistency.

Another object is to provide a method for producing fully coatedindividual particles, for instance, coated roofing granules.

A further object is to provide a method for extending compositioncoatings with aggregate material and in measured quantities.

Another object is to provide a method for bringing together measuredquantities of coating materials and aggregate particles, and tocontinuously form one or more layers comprising said materials on asuitable base.

'A further object is to provide a method for Fig. 1, and

producing a structure of composition material,

measured quantity of particulate material to the point of coatingremoval or in advance thereof, so that the same will be discharged bythe distributor bristles with the coating material, and in a manner suchthat the individual particles of particulate material receive a coatingthereof before being discharged.

These and other objects of the invention will in part be understood andin part be more particularly pointed out in the following descriptionand in the claims taken in conjunction with the accompanying drawing,wherein Fig. 1 is a side elevation of apparatus embodying the invention;

Fig. 2 is a plan .view of the apparatus shown in Fig. 3 is an enlargedsectional view of the particulate feeding and coating apparatus shown inFig. 1.

Referring to Figs. 1 to 3 inclusive, Fig. 1 shows a coating machine suchas disclosed in my aforesaid copending application, now Patent No.2,156,286, and which comprises a plurality of coating units l0 and H,each comprising a hopper I2, a driven rotatable roll I4 to feed ameasured layer of coating composition and forming the bottom of thehopper, and a distributing member, for instance, a rotatable bristleimpeller l6 operating on the fed composition and discharging a particlestream thereof on a receiving surface below. The units are suitablysupported in a frame l8 by suitable brackets or other supporting means,more particularly illustrated in said prior application. An endlessconveyor 20 is positioned below the coatingunits, preferably in closeproximity to but out of contact with the distributor {l6 and serves toconvey suitable base materialjli which may be a web of mineral surfacedcomposition roofing material or in-,, dividual shingle elements thereof,which have been made into blanks by a cutting roll 24, for

coating, by the. discharging coating streams] Where a web of material isfed, such may be sub-w sequently delivered in coated condition to a pullroll assembly 26, whereby the web may be passed into contact with acutting roll 28 and severed into sections of desired size, and thesedelivered to a conveyor belt 30 for further operations.

In the operation disclosed in Fig. 1, the base material to be coatedwill receive one or two applications of coating composition, dependingon whether one or both of the coating units are in operation. Thus, forexample, upon passing under the first coating unit I 0, the basematerial will receive a base coating of the composition in the hopper ofthis unit, and on subsequently passing beneath the coating unit II, willreceive a second coating. It will be understood that further of thesehoppers may be positioned along the path of the conveyor 20, andadditional coatings be applied to the base material. Likewise, insteadof using tl.e composition as a coating, layers of suitable thickness maybe formed of the composition upon the conveyor 20, and such layersremoved to form various products, for example, where the composition isone of cement, suitable shingle slabs or wallboard might be produced.

-In these coating operations, it is sometimes desired to include certainaggregate or particulate material with the coating material orcomposition, and it is a feature of the invention to provide a methodthat will enable such material to be added to the coating compositionfrom a separatesource of supply so that it becomes well mingledtherewith, and such that substantially each particle of the aggregatebecomes well treated with the composition. Moreover, the procedure to bedescribed enables me to obtain a uniform distribution of the aggregateand provides all portions of the fed coating composition with theirproper amounts of aggregate material. Examples of aggregate materialthat may be handled in accordance with this invention are, for example,comminuted fibrous, flocculent or granular materials such as asbestos,ground cork, mica flakes, graphite, powdered coloring pigments, crushedslate, tile or silica. One or more of these may be brought together withvarious coating compositions, for example, an argillaceous cement suchas a hydraulic cement like portland or aluminate, water emulsions suchas of bitumen, or phenolic resins, resinous molding compounds wettedwith suitable solvents, casein compositions, rubber or latex in suitablesolvents, and silicate coatings, for instance, soluble sodium silicate.Preferably, these compositions will be in a plastic or sludgyconditionsuch that they may be fed by the character of hopper and feed rollapparatus disclosed in the drawing. ever, it will be understood thatwhere these coat ings are of a more liquid character that suitable feedmechanism, for example, of the character disclosed in my applicationfiled of even date herewith, may be substituted in lieu of the hopperl2.

In order-to feed the aggregate extending or particle core (hereinafterreferred to as aggregate material) material, a suitable hopper 32 may beprovided having a feed roll 34 forming the some instances, a guide suchas a. chute 38 may be employed to control the point of application ofthe aggregate material. Also, sometimes it is preferred that thematerial from the hopper 32 reach the coating layer l8 somewhat inadvance,

for instance, a short distance before contact by The latter is founddesirable the distributor l6. where the operation is one to fully coatparticles, such as when coated roofing granules are being made; also,when the aggregate material being fed is of a light character, so as tokeep the Howsame out of the influence of the air stream of the impeller.Upon reaching the coating layer I8, the particles of the stream 36 comeinto the influence of the brush l8 and are beaten and well mingled withthe coating and then discharged as by impelling against the basematerial 22 or conveyor 20, as the case may be. The described procedureassures an intimate co tact between the particles of the aggregate andthe coating composition, so that the particles of commlnuted materialare substantially individually coated with the coating compositionbefore dis charging.

The guide 38 may be in the form of. a sheet metal plate supported byrocker arm 39 and secured thereto by bolts 40. The arm 39 may be clampedto a stationary support such as a rod 4|, by set screws 42. Obviously,in this manner the chute or guideway 38 may be adjusted to any suitableradial position. The plate 38 may also be provided with elongated slots44 so that the discharge end of the guide may be somewhat adjusted inthis manner. The guide plate may further be provided with one or morepartition plates 46, where two or more different aggregates are beingfed. The partition 48 is provided at its outer edges with flatunder-fingers 48 carrying clamp screws 50. When the member 46 is used,it will generally be in the same relative position as the partitionmember or members 52 of the hopper 32 and the partition plate 54 of thecoating composition hopper I2. The feed mechanism may also be providedwith one or more baflie 'plates 56 supported between the side frames l8.These may be positioned to further guide the particle stream or toprevent outside influence on such stream of particles. Also, theimpellers 5 may be covered by a suitable shield 58 to prevent throwingof the coating composition by this member.

The aggregate feed roll 34 may be driven by any suitable means, such asby a belt 63 and pulleys 62 and 64 secured respectively to the shafts ofthe rolls l4 and"'34. Power may be applied for rotating the coatingcomposition feed rolls l4 and the distributing or discharge elements l6by any suitable means, for example, a belt (not shown) engaging a pulley68 carried upon the feed roll shaft'ltl of the coating unit I0. Theimpeller l6 of this unit may be driven by a set of gears 12 mounted onthe shaft 10 of the coating feed roll and shaft I4 of the impeller IS.The impeller I6 and feed roll H of the coating unit H may be driven fromthe shaft 14 by means of cooperating gears I6. It is to be noted thatthe gears 12 and 15 are so arranged that the distributors l6 are drivenat a higher speed than the feed rolls Hi. It is obvious that thespecific type of driving mechanism for the various rolls may be variedas desired. A specific embodiment has been shown for purposes ofillustration only. The impellers and also the feed rolls of both hoppersi 2 and 32,

may be driven by separate motors, if desired,.in

provided as there are coating units.

order to obtain any desired speed differential between these members.

It will be understood that while the aggregate feed unit 32 has beenshown in the drawing only in connection with the coating unit II, asimilar unit may be provided for the coating unit Ill. Moreover, it willbe understood that as many of these aggregate feed mechanisms may be Itmay be seen that by properly controlling the speed of rotation of theroll 34, the rate of delivery of aggregat' imaterial to the coatingcarrying roll I4, may be] controlled. Likewise, the speed of the roll" l4will control the rate of delivery of coating material. These speedswill be selected for the type of result that is desired, that is,whether the combined materials are to be formed, for instance, into acoating layer or into individually coated particles. It will beunderstood that the aggregate materials may be readily combined with thecoating composition and in any density, and will be thoroughly beatenand mingled with the coating material before delivery by the impeller orother distributing device.

The described arrangement .is particularly useful for coating granulesor other particles which it may be desired to provide with an encasingfilm or layer of coating material. For examplefit may be desired to coatindividual roofing granules of a size between 8 and 12 mesh, such as arecustomarily used for surfacing asphalt roofing materials. To accomplishthis, base granules or cores are placed in the hopper 32.and a suitablecoating composition, for instance, a colored hydraulic cementcomposition, is placed in the hopper l2 of the coating unit' II. Therate of feed of the roll 34 will be controlled so that a properproportion of base granules are fed to the layer 31 of coating materialcarried by the feed roll l4. In the operation, the granules will bebrought into contact with the coating material and then discharged bythe distributor or impeller 16 in a coated condition. The impeller IEwill be of the bristle or spring filament type. During contact by theimpeller, the base granules receive what is believed to be a rotary orspinning action whereby they are fully coated. By adjusting theviscosity of the coating composition, the speed of the bristle impeller16 and the rolls l4 and 34, the point of application of the granules, aswell as the amount of wipe of the brush bristles, the granules may beprojected in a fully coated condition and coated to any desired extentand with coatings of desired characteristics. The coated granules may bedeposited by the distributor [6 upon the moving conveyor 28, which maybe in the nature of a screen or rubber belt of sufiicient length, andmay be collected at a. subsequent point, for instance, by dropping intothe collection tray 88.

Obviously, the distance to be traveled by the coated granules from thepoint of deposit to their point.of collection will depend upon thenature of the coating and any further operations which it may be desiredto perform on the coated pieces before reaching the collection point. Incertain cases it may be desired to apply the coated granules directly toa base material, for instance, the web 22 carried by the conveyor toprovide an ornamental or weather surfacing therefor. Where the basematerial has received a prior coating layer from the coating unit III,the freshly coated granules may be de-- posited on such coating and bebonded thereto.

Suitable vibrators 82 may also be provided for keeping the coatedgranules agitated, where they are directly deposited upon the conveyor28. The vibrators may be, for instance, of an electro-magnetic type andmay be positioned against the under side of the conveyor belt as shownin Fig. 1. A similar vibrator 84 may be provided for the guide plate 38of the aggregate feed mechanism. It will be noted that the impeller l6may be provided with a baflle 86 in line with the partition 54 of thecoating composition hopper so as to separate compositions of different.character as they are impelled on the web 22. The baflle 86 may also beprovided with suitable vibrating means, for instance, that disclosed inmy prior copending application, now Patent No. 2,156,286, aforesaid, todislodge any composition which may adhere thereto. This means maycomprise a pair of transverse rods 88, supporting the baflle 86. Springs90, surrounding the rods 88 and engaging the frame l8, urge the bafliesagainst stops carried by the rods. A pin 93 (Fig. 2) is slidably carriedin the frame l8, and at one end bears against the baffle 86 and at theother end against a cam 94 which may be mounted, for example, on theshaft 96 of the impeller l6. As the cam 94 rotates, the pin 93 is causedto reciprocate transversely causing a corresponding movement of thebailie plate 86.

The apparatus of my invention may readily be used to deliver coatingcompositions containing considerable filler; and produce mastic forms onthe conveyor 26 below. In some in.- stances, it may be necessary to heatthe distributor IE or even the feed rolls l4, in which case suitablesteam piping may be provided for such purpose through the center of therespective members, all as more particularly disclosed, for example, inFig. 15 of my prior application (now Patent No. 2,156,286) aforesaid. Insuch an operation the coating may be, for example, a hot bitumen or anyother character of congealable coating.

In operating the mechanism of Fig. 1, for instance, to coat a roofingweb with a base cementitious composition and with a surface cementitiouscoating containing a fireproofing and strength provided aggregate, thefollowing takes place: The hopper l2 of the coating unit [8 is providedwith a base cement coating composition and the hopper l2 of coating unit"I I, with a coating of similar character but which may include somecoloring material. The hopper 32 is provided with a supply of comminutedasbestos with or without further coloring material. The coatingcompositions in the hoppers l2 will preferably be in a plastic or sludgycondition. Power is supplied for rotating the feed rollsand distributingmechanism, and the rolls l4 each feed a predetermined layer of thecement composition from their respective hoppers to the point of contactof bristle impellers l6, by which the composition is applied in aparticle stream to moving web 22 to reform a layer thereon. Thesecondary coating or surface coating provided by the coating unit II,will immediately followthe first or base coating provided by the coatingunit l0, and. the former will carry with it a deposit of aggregatematerial from the hopper 32, which in this case will be asbestos fiberwith or without a coloring aggregate. The aggregate will be dropped uponthe secondary coating as it is carried in the roll l4 and slightly inadvance of the distributor so that this material will be well coatedwith the cement composition before being projected against the base web.Essentially, continuous increments of the deposited layer are beaten tocommingle the coating and particulate pieces and to coat the latter. Inthis manner, a structure is provided having a base cementitious coatingand a surface colored coating carrying a fireproofing and strengthgiving aggregate. Where the base web is, for instance, an asphalt coatedgranule surfaced one, the force may be sufficient to cause the ofrotation or motion shown in the drawing for the various moving parts arethe preferred directions.

From the above description, it will be seen that I have provided novelmethods for combining aggregate particles and coating compositions, andmethods for forming individually coated particles. The disclosedembodiment of the invention has been set forth for the purpose ofillustration only. It will be understood that many changes may be madeand will suggest themselves to those skilled in the art Withoutdeparting from the spirit and scope of my invention, which is only to belimited in accordance with the following claims when taken inconjunction with the prior art. 7

I claim:

1. In the method of treating particulate material, the improvementcomprising feeding coating material and a particulate substance fromseparate sources of supply, forming a layer of said coating materialincluding amultiplicity of pieces of said particulate substance, andbeating continuous increments of said layer to commingle said coatingand particulate pieces and coat the latter.

2. In the method of treating particulate material, the improvementcomprising feeding a plastic coating material and particulate substancefrom separate sources of supply, forming a layer having said coating anda multiplicity of pieces of said particulate substance applied insuperposed relation, and beating continuous increments of said layer tocommingle said coating and particulate pieces and coat the latter.

3. In the method of treating particulate material, the improvementcomprising feeding plastic coating material and particulate substancefrom separate sources of supply, forming a layer comprising said plasticcoating and particulate substance applied in superposed relation andcomprising predetermined amounts of said plastic coatingmaterial andparticulate substance and beating continuous increments of saidcomposite layer to commingle said coating and particulate substance andcoat the pieces of particplicity of pieces of said particulate substanceupon said layer and beating continuous increments of said compositelayer to commingle' said coating and particulate pieces and coat thelat-.

ter. J g

5. In the method of coating roofing granules with a plastic coating theimprovement comprising forming a layer of plastic coating material,

adding a multiplicity of individual granules to a surface of saidcoating layer, giving the granules of said composite layer asubstantially rotary motion whereby to coat them with said 'fiber, andbeating continuous increments of said layer to commingle said cementcomposition and mineral fiber pieces and coat the latter.

7. The method of treating particulate material and surfacing a basetherewith comprising feeding plastic coating material and particulatesubstance from separate sources of supply, forming a layer having saidcoating and a multiplicity of pieces of said particulate substanceapplied in superposed relation, beating continuous increments of saidlayer to commingle said coating and particulate pieces and coat thelatter, and projecting a stream of the coated particulate material upona base having relative motion with respect thereto to form a surfacingthereon.

8. The method of treating particulate material with plastic and forminga layer product therefrom comprising feeding plastic coating materialand particulate substance from separate sources of supply, forming alayer having said coating and a multiplicity of pieces of saidparticulate substance applied in superposed relation, beating continuousincrements of said layer to commingle said coating and particulatepieces and coat the latter, projecting a stream of the coatedparticulate material upon a re ceiving surface having relative motionwith respect thereto, and forming a layer of said material ofsubstantial thickness.

9. The method of treating a particulate aggregate with plastic materialand applying the same to a receiving surface, comprising withdrawing ameasured layer of plastic material from a source of supply, superposinga measured amount of solid particulate aggregate upon said plasticlayer, beating continuous increments of said composite layer tocommingle said plastic material and pieces of particulate aggregate, andimpelling a stream of said commingled material upon a receiving surface.I

10. The method of treating particulate material with a plastic coatingmaterial comprising substantially continuously feeding coating materialand particulate substance from separate sources of supply, substantiallycontinuously moving a layer of the coating with respect to a stream ofsaid'particulate substance, substantially continuously superposing amultiplicity of pieces of said particulate substance upon said coatinglayer, substantially continuously beating increasing increments of saidcomposite layer to commingle said coating and particulate pieces,

and distributing coated particulate pieces of said rial comprisingfeeding a stream of plastic coating to a distributing position, addingsolid particulate material to the plastic coating at said distributingposition, commingling said coating and particulate material and spinningthe pieces of particulate material whereby to provide them with asubstantially continuous surfacing of said coating, throwing said coatedparticulate pieces into space, and collecting the coated material upon asurface having lateral motion with respect thereto. p

12. The method of treating a particulate aggregate with coatingcomposition and applying the same to a receiving surface comprisingforming a layer of the plastic coating material, moving said layer to adistributing position feeding a a stream of particulate aggregratematerial to said coating layer in advance of said distributing position,commingling said aggregate material and coating, and impelling aparticle stream of the commingled material upon .a receiving surface toform a substantially continuous layer thereon.

ous increments of said composite layer to com- 20 mingle said cement andgranular material and coat said granular material with said cement. and,before said cement has set, projecting said coated granular materialupon a base having relative motion with respect thereto whereby to bondsaid granular material to said base.

14. The method of treating particulate aggregate material with coatingand superimposing a plurality of coatings certain of which include saidaggregate comprising feeding a plurality of coating layers, surfacingselective layers with solid particulate aggregate material,l'ieatingcontinu-v ous increments of said surfaced coating material tocomminglesaid coating and pieces bf particulate aggregate and coat thelatter and beating continuous increments of said unsurfac'ed coat-- ing,impelling particle streams of the beaten nortions of said layers againsta surface having relative motion with respect to said streams, andprojecting said streams such that-they produce superposed laminations onsaid surface.

' NORMAN P. HARSHBERGER.

